This invention relates to a last round detection (i.e., sensing) device and, more particularly, to such a device that is for use with an ammunition storage drum for a modern multi-barrel high rate-of-fire machine gun, such as the 30 mm, Model GAU-8 ("Gatling" type) manufactured and sold by the General Electric Company, Burlington, Vt. 05401.
In ammunition storage devices or reservoirs of the drum type for modern multi-barrel high rate-of-fire machine guns, rounds of ammunition are stored within the ammunition storage drum in abutting positions and around a helical-like core member. As the core member is rotated, the rounds are individually transported to an outlet in the drum. Flexible ammunition chuting is interposed between, and is connected to, the outlet of the ammunition storage drum and the receiver of the gun; and, the chuting is used for handling and transporting the rounds of unfired ammunition from the drum to the gun, and the cases of spent ammunition from the gun back to the drum.
Since the gun fires at a high rate-of-fire, there is the possibility that spent cases which have been returned to the drum will be transported again to the gun and chambered. Obviously, this is undesirable, and to prevent it, prior art "last round" sensing devices, which cut off power to the gun after sensing the last round, have been positioned in the outlet (hereinafter referred to as the "exit" or "exit unit"), FIG. 3, to prevent this occurrence. Although these prior art sensing devices are satisfactory at the present high rates-of-fire, they would not be at higher rates-of-fire, where the length of the flexible ammunition chuting (and the time involved in moving ammunition through this length of chuting) from the exit unit to the gun is very short.
What is needed at contemplated higher rates-of-fire to prevent the chambering of cases of spent ammunition, and is not presently available, is a last round detecting (i.e., sensing) device which will sense the last round a sufficiently long lead time before it reaches the exit unit during the overrun after power cut off.
With our inventive last round detection device we have fulfilled that need; and, thereby, we have significantly advanced the state-of-the-art.